The present invention relates to methods for preparing carbon containing fuels for smoking articles and to the fuel products produced thereby. These methods and fuels are especially useful in making cigarette--type smoking articles that produce an aerosol resembling tobacco smoke, but which contain no more than a minimal amount of incomplete combustion or pyrolysis products.
Many tobacco substitute smoking materials have been proposed through the years, especially over the last 20 to 30 years. These proposed tobacco substitutes have been prepared from a wide variety of treated and untreated materials, especially cellulose based materials. Numerous patents teach proposed tobacco substitutes made by modifying cellulosic materials, such as by oxidation, by heat treatment, or by the addition of materials to modify the properties of the cellulose. A substantial list of such substitutes is found in U.S. Pat. No. 4,079,742 to Rainer et al.
Many patents describe the preparation of proposed smoking materials from various types of carbonized (i.e., pyrolyzed) cellulosic material. These include U.S. Pat. No. 2,907,686 to Siegel, U.S. Pat. No. 3,738,374 to Bennett, U.S. Pat. Nos. 3,943,941 and 4,044,777 to Boyd et al., U.S. Pat. Nos. 4,019,521 and 4,133,317 to Briskin, U.S. Pat. No. 4,219,031 to Rainer, U.S. Pat. No. 4,286,604 to Ehretsmann et al., U.S. Pat. No. 4,326,544 to Hardwick et al., U.S. Pat. No. 4,481,958 to Rainer et al., Great Britain Patent No. 956,544 to Norton, Great Britain Patent No. 1,431,045 to Boyd et al., and European Patent Application No. 117,355 to Hearn, et al. In addition, U.S. Pat. No. 3,738,374 to Bennett teaches that tobacco substitutes may be made from carbon or graphite fibers, mat or cloth, most of which are made by the controlled pyrolysis of cellulosic materials, such as rayon yarn or cloth.
Other prior art patents describe the use of carbon or pyrolyzed cellulosic material either as a component of proposed smokable materials or as a filler for such materials. These include U.S. Pat. No. 1,985,840 to Sadtler, U.S. Pat. Nos. 3,608,560, 3,831,609, and 3,834,398 to Briskin, U.S. Pat. No. 3,805,803 to Hedge, U.S. Pat. No. 3,885,574 to Borthwick et al., U.S. Pat. No. 3,931,284 to Miano et al., U.S. Pat. No. 3,993,082 to Martin et al., U.S. Pat. No. 4,199,104 to Roth, U.S. Pat. Nos. 4,244,381 and 4,256,123 to Lendvay et al., U.S. Pat. No. 4,340,072 to Bolt, U.S. Pat. No. 4,347,855 to Lanzillotti et al., U.S. Pat. No. 4,391,285 to Burnett et al., and U.S. Pat. No. 4,474,191 to Steiner.
Still other patents describe the partial pyrolysis of cellulosic materials to prepare proposed smoking materials. These include U.S. Pat. Nos. 3,545,448 and 4,014,349 to Morman et al., U.S. Pat. Nos. 3,818,915, 3,943,942 and 4,002,176 to Anderson, and U.S. Pat. No. 4,079,742 to Rainer et al.
Despite decades of interest and effort, it is believed that none of the aforesaid smoking materials have been found to be satisfactory as a tobacco substitute. Indeed, despite extensive interest and effort, there is still no smoking article on the market which provides the benefits and advantages associated with conventional cigarette smoking, without delivering considerable quantities of incomplete combustion and pyrolysis products.